When showing or delivering a moving image, it is common to conceal a portion of the moving image for various purposes such as personal information protection. Such image concealment (masking) is done, for example, when using a medical diagnostic video (a moving image obtained by an ultrasonic diagnostic device or an endoscope) or a surgery video for other than its originally intended purpose, for example, medical education purposes.
FIG. 19 is a diagram showing a diagnostic moving image obtained by an ultrasonic diagnostic device. In a diagnostic moving image 81, personal information for identifying the patient is also recorded as shown in a region 82. In medical practice, a medical practitioner can visually check personal information to make sure that the diagnostic moving image based on which he is making a diagnosis is one actually taken of the patent he is seeing.
On the other hand, when showing such a diagnostic moving image to an audience for medical education purposes, the personal information portion of the image must be masked to protect the personal information of the patient.
Further, in the case of an image such as a surgery video, in which the patient can be identified directly from the image being shown, masking must be applied to the image to such a degree that the patient shown in the image cannot be identified.
Patent document 1: Japanese Unexamined Patent Publication No. S64-36460
Patent document 2: Japanese Patent No. 3552945